Thermal Responses in the Evolutionary Ecology of Aquatic Insects
01 Jan 1982-Annual Review of Entomology (Annual Reviews 4139 El Camino Way, P.O. Box 10139, Palo Alto, CA 94303-0139, USA)-Vol. 27, Iss: 1, pp 97-117
About: This article is published in Annual Review of Entomology.The article was published on 1982-01-01. It has received 604 citations till now. The article focuses on the topics: Evolutionary ecology & Phage ecology.
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TL;DR: This literature review has focused this literature review around four key principles to highlight the important mechanisms that link hydrology and aquatic biodiversity and to illustrate the consequent impacts of altered flow regimes.
Abstract: The flow regime is regarded by many aquatic ecologists to be the key driver of river and floodplain wet- land ecosystems. We have focused this literature review around four key principles to highlight the important mech- anisms that link hydrology and aquatic biodiversity and to illustrate the consequent impacts of altered flow regimes: Firstly, flow is a major determinant of physical habitat in streams, which in turn is a major determinant of biotic com- position; Secondly, aquatic species have evolved life history strategies primarily in direct response to the natural flow regimes; Thirdly, maintenance of natural patterns of longitu- dinal and lateral connectivity is essential to the viability of populations of many riverine species; Finally, the invasion and success of exotic and introduced species in rivers is facilitated by the alteration of flow regimes. The impacts of flow change are manifest across broad taxonomic groups including riverine plants, invertebrates, and fish. Despite growing recognition of these relationships, ecologists still struggle to predict and quantify biotic responses to altered flow regimes. One obvious difficulty is the ability to distin- guish the direct effects of modified flow regimes from im- pacts associated with land-use change that often accom- panies water resource development. Currently, evidence about how rivers function in relation to flow regime and the flows that aquatic organisms need exists largely as a series of untested hypotheses. To overcome these problems, aquatic science needs to move quickly into a manipulative or experimental phase, preferably with the aims of restora- tion and measuring ecosystem response.
3,018 citations
Cites background from "Thermal Responses in the Evolutiona..."
...Modified thermal patterns and day-length cues have been shown not only to disrupt insect emergence patterns but also to reduce population success (Ward and Stanford 1982)....
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TL;DR: The hyporheic corridor concept emphasizes connectivity and interactions between subterranean and surface flow on an ecosystem level for floodplain rivers as mentioned in this paper, which is a complementary concept to others which focus on surficial processes in the lateral and longitudinal dimensions.
Abstract: 1. This review focuses on the connectivity between river and groundwater ecosystems, viewing them as linked components of a hydrological continuum. Ecological processes that maintain the integrity of both systems and those that are mediated by their ecotones are evaluated.
2. The hyporheic zone, as the connecting ecotone, shows diverse gradients. Thus it can be characterized by hydrological, chemical, zoological and metabolic criteria. However, the characteristics of the hyporheic zone tend to vary widely in space and time as well as from system to system. The exact limits are difficult to designate and the construction of static concepts is inadequate for the representation of ecological processes. The hyporheic interstices are functionally a part of both the fluvial and groundwater ecosystems.
3. The permeability of the ecotone depends on the hydraulic conductivity of the sediment layers which, because of their heterogeneity, form many flowpath connections between the stream and the catchment, from the small scale of a single microhabitat to the large scale of an entire alluvial aquifer. Local up- and downwellings are determined by geomorphologic features such as streambed topography, whereas large-scale exchange processes are determined mainly by the geological properties of the catchment. Colmation—clogging of the top layer of the channel sediments—includes all processes leading to a reduction of pore volume, consolidation of the sediment matrix, and decreased permeability of the stream bed. Consequently, colmation can hinder exchange processes between surface water and groundwater.
4. Physicochemical gradients in the interstices result from several processes: (i) hyporheic flow pattern and the different properties of surface and groundwaters; (ii) retention, caused by the filtering effect of pore size and lithologic sorption as well as the transient storage of solutes caused by diminished water velocities; (iii) biogeochemical transformations in conjunction with local residence time. Each physicochemical parameter may develop its own vertical dynamics laterally from the active channel into the banks as well as longitudinally because of geomorphologic changes.
5. The river–groundwater interface can act as a source or sink for dissolved organic matter, depending on the volume and direction of flow, dissolved organic carbon concentrations and biotic activity. Interstitial storage of particulate organic matter is influenced mainly by grain size distribution and by spates involving bedload movement that may import or release matter, depending on the season. After initial transient and abiotic storage, hyporheic organic matter is mobilized and transformed by the biota. Micro-organisms account for over 90% of the community respiration. In subterranean waters most bacteria are attached to surfaces and remain in a biofilm.
6. Hyporheic interstices are functionally significant for phreatic and riverine metazoans because they act as a refuge against adverse conditions. The net flow direction exerts a dominant influence on interstitial colonization, but many other factors also seem to be important in structuring the hyporheos.
7. The hyporheic corridor concept emphasizes connectivity and interactions between subterranean and surface flow on an ecosystem level for floodplain rivers. It is a complementary concept to others which focus on surficial processes in the lateral and longitudinal dimensions.
8. The ecological integrity of groundwater and fluvial systems is often threatened by human activities: (i) by reducing connectivity; (ii) by altering exchange processes; and (iii) by toxic or organic contamination.
1,321 citations
TL;DR: In this article, the authors explore the concept of the natural thermal regime, review how dam operations modify thermal regimes, and discuss the ecological implications of thermal alteration for freshwater ecosystems and identify five major challenges for incorporating water temperatures into environmental flow assessments, and describe future research opportunities and some alternative approaches for confronting those challenges.
Abstract: SUMMARY 1. Despite escalating conflict over fresh water, recent years have witnessed a growing realisation that human society must modify its behaviour to ensure long-term ecological vitality of riverine ecosystems. In response, ecologists have been increasingly asked to guide instream flow management by providing ‘environmental flow’ prescriptions for sustaining the ecological integrity of riverine systems. 2. Environmental flows are typically discussed in the context of water releases from dams and water allocation for extraction (such as for urban use or irrigation), where there is general agreement that rivers need to exhibit some resemblance of natural flow variability necessary to support a functioning ecosystem. Although productive dialogue continues on how best to define environmental flows, these discussions have been focused primarily on water quantity without explicit consideration of many components of water quality, including water temperature – a fundamental ecological variable. 3. Many human activities on the landscape have modified riverine thermal regimes. In particular, many dams have modified thermal regimes by selectively releasing hypolimnetic (cold) or epilimnetic (warm) water from thermally stratified reservoirs to the detriment of entire assemblages of native organisms. Despite the global scope of thermal alteration by dams, the prevention or mitigation of thermal degradation has not entered the conversation when environmental flows are discussed. 4. Here, we propose that a river’s thermal regime is a key, yet poorly acknowledged, component of environmental flows. This study explores the concept of the natural thermal regime, reviews how dam operations modify thermal regimes, and discusses the ecological implications of thermal alteration for freshwater ecosystems. We identify five major challenges for incorporating water temperatures into environmental flow assessments, and describe future research opportunities and some alternative approaches for confronting those challenges. 5. We encourage ecologists and water managers to broaden their perspective on environmental flows to include both water quantity and quality with respect to restoring natural thermal regimes. We suggest that scientific research should focus on the comprehensive characterisation of seasonality and variability in stream temperatures, quantification of the temporal and spatial impacts of dam operations on thermal regimes and clearer elucidation of the relative roles of altered flow and temperature in shaping ecological patterns and processes in riverine ecosystems. Future investigations should also concentrate on using this acquired knowledge to identify the ‘manageable’ components of the thermal regime, and develop optimisation models that evaluate management
732 citations
Cites background from "Thermal Responses in the Evolutiona..."
...The thermal impacts associated with dam operations in riverine ecosystems are well recognised (Ward & Stanford, 1982; Ward, 1985; Petts, 1986; Webb & Walling, 1996); although they are examined much less often than river hydrology....
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...Another potential consequence of warmer winter temperatures is an increase in the growth of aquatic insects, resulting in winter rather than spring or early summer emergence (Ward & Stanford, 1982)....
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TL;DR: In this article, the authors proposed a management belief system that relies upon natural habitat restoration and maintenance, as opposed to artificial propagation, installation of artificial instream structures (river engineering) and predator control.
Abstract: Large catchment basins may be viewed as ecosystems in which natural and cultural attributes interact. Contemporary river ecology emphasizes the four-dimensional nature of the river continuum and the propensity for riverine biodiversity and bioproduction to be largely controlled by habitat maintenance processes, such as cut and fill alluviation mediated by catchment water yield. Stream regulation reduces annual flow amplitude, increases baseflow variation and changes temperature, mass transport and other important biophysical patterns and attributes. As a result, ecological connectivity between upstream and downstream reaches and between channels, ground waters and floodplains may be severed. Native biodiversity and bioproduction usually are reduced or changed and non-native biota proliferate. Regulated rivers regain normative attributes as distance from the dam increases and in relation to the mode of dam operation. Therefore, dam operations can be used to restructure altered temperature and flow regimes which, coupled with pollution abatement and management of non-native biota, enables natural processes to restore damaged habitats along the river’s course. The expectation is recovery of depressed populations of native species. The protocol requires: restoring peak flows needed to reconnect and periodically reconfigure channel and floodplain habitats; stabilizing baseflows to revitalize food-webs in shallow water habitats; reconstituting seasonal temperature patterns (e.g. by construction of depth selective withdrawal systems on storage dams); maximizing dam passage to allow recovery of fish metapopulation structure; instituting a management belief system that relies upon natural habitat restoration and maintenance, as opposed to artificial propagation, installation of artificial instream structures (river engineering) and predator control; and, practising adaptive ecosystem management. Our restoration protocol should be viewed as an hypothesis derived from the principles of river ecology. Although restoration to aboriginal state is not expected, nor necessarily desired, recovering some large portion of the lost capacity to sustain native biodiversity and bioproduction is possible by management for processes that maintain normative habitat conditions. The cost may be less than expected because the river can do most of the work.
728 citations
TL;DR: In this article, the long-term pattern of physicochemical variability in conjunction with the complexity and stability of the substratum establishes a physical habitat template that theoretically influences which combinations of behavioral, physiological and life history characteristics constitute appropriate "ecological strategies" for persistence in the habitat.
Abstract: Spatial and temporal environmental heterogeneity in lotic ecosystems can be quantitatively described and identified with characteristic levels of ecological organization. The long-term pattern of physicochemical variability in conjunction with the complexity and stability of the substratum establishes a physical habitat template that theoretically influences which combinations of behavioral, physiological and life history characteristics constitute appropriate “ecological strategies” for persistence in the habitat. The combination of strategies employed will constrain ecological response to and recovery from disturbance. Physical habitat templates and associated ecological attributes differ geographically because of biogeoclimatic processes that constrain lotic habitat structure and stability and that influence physicochemical variability and disturbance patterns (frequency, magnitude, and predictability). Theoretical considerations and empirical studies suggest that recovery from natural and anthropogenic disturbance also will vary among lotic systems, depending on historical temporal variability regime, degree of habitat heterogeneity, and spatial scale of the perturbation. Characterization of physical habitat templates and associated ecological dynamics along gradients of natural disturbance would provide a geographic framework for predicting recovery from anthropogenic disturbance for individual streams. Description of lotic environmental templates at the appropriate spatial and temporal scale is therefore desirable to test theoretical expectations of biotic recovery rate from disturbance and to guide selection of appropriate reference study sites for monitoring impacts of anthropogenic disturbance. Historical streamflow data, coupled with stream-specific thermal and substratum-geomorphologic characteristics, are suggested as minimum elements needed to characterize physical templates of lotic systems.
598 citations
References
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TL;DR: It is hypothesized that producer and consumer communities characteristic of a given river reach become established in harmony with the dynamic physical conditions of the channel.
Abstract: From headwaters to mouth, the physical variables within a river system present a continuous gradient of physical conditions. This gradient should elicit a series of responses within the constituent...
9,145 citations
Book•
01 Jan 1956
TL;DR: The most comprehensive reference on the aquatic larval stages of the 149 Nearctic genera of Trichoptera, comprising more than 1400 species in North America, is as discussed by the authors.
Abstract: Caddisflies are one of the most diverse groups of organisms living in freshwater habitats, and their larvae are involved in energy transfer at several levels within these communities. Caddisfly larvae are also remarkable because of the exquisite food-catching nets and portable cases they construct with silk and selected pieces of plant and rock materials. This book is the most comprehensive existing reference on the aquatic larval stages of the 149 Nearctic genera of Trichoptera, comprising more than 1400 species in North America. The book is invaluable for freshwater biologists and ecologists in identifying caddisfly in the communities they study, for students of aquatic biology as a guide to the diverse fauna of freshwater habitats, and for systematic entomologists as an atlas of the larval morphology of Trichoptera. In the General Section, the biology of caddisfly larvae is considered from an evolutionary point of view. Morphological terms are discussed and illustrated and a classification of the Nearctic genera is given. Techniques are outlined for collecting and preserving larval specimens and for associating larval with adult stages. The Systematic Section begins with a key to larvae of the 26 families of North American Trichoptera. Each chapter in this section is devoted to a particular family, providing a summary of biological features and a key to genera, followed by a two-page outline for each genus with illustrations facing text. This outline provides information on general distribution, number of species, distinctive morphological features, and biological data including construction behaviour. An important feature of the book is the habit illustrations of larvae and cases of a selected species in each genus, along with illustrations of details of significant morphological structures. Each generic type is thus presented as a recognizable whole organism adapted in elegant ways to particular niches of freshwater communities. This revised edition includes advances in knowledge on the classification and biology of Trichoptera up to 1993 - an interval of 17 years since the first edition. An additional eight families and thirteen genera are included for the first time. Through reorganization of the families into three suborders, a biological context has been established for the systematic section.
978 citations
TL;DR: The earliest dams were probably constructed by blocking the stream with earth as discussed by the authors, and these dams were held in place by their own weight pressing against their foundations, and usually have a long sloping downstream toe to prevent overtipping.
Abstract: Most of the primary civilizations of the world emerged in or near river valleys. The construction of dams and other hydraulic structures is, therefore, one of the oldest branches of engineering (e.g. 11, 105). The earliest dams were probably built for the purposes of irrigation, flood control, and water supply. Later, water was impounded so that its subsequent controlled release could provide a source of energy, first by the use of waterwheels and later by the use of hydroelectric generators. Other purposes include the maintenance of an adequate river flow through the year for navigation, and the provision of facilities for recreation. Most modem reservoirs are designed for two or more of these purposes. Usually "the role of water storage reservoirs . . . is to impound water in periods of higher flows so that it may be released gradually during periods of lower flows" (135), but sometimes the sole purpose of the impoundment is to provide a new body of standing water for use as such; for example, for fishing or boating, or for waste-heat dissipation from a thermoelectric generating plant. The earliest dams were probably constructed by blocking the stream with earth. Such dams are still constructed. In its simplest form. an earth-fill dam is a pile of compacted earth extending across a stream with a fairly gentle slope both upstream and downstream. Similar to earth-fill dams are rock-fill dams composed of quarried rock or natural boulders or gravel with a layer of impervious material on the upstream face. A later development in dam construction was the invention of the masonry dam, probably in Spain (150). The earliest masonry dams were of the gravity type. Such dams are held in place by their own weight pressing against their foundations, and usually have a long sloping downstream toe to prevent overtipping.
815 citations
TL;DR: It is suggested that an 'optimum' thermal regime exists where adult size and fecundity are maximized; temperature regimes warmer or cooler than the "optimum'' result in small and less fecund adults.
Abstract: Adult body size and fecundity of several species of hemimetabolous aquatic insects were shown to depend largely on thermal conditions during larval growth We suggest that an "optimum" thermal regime exists where adult size and fecundity are maximized; temperature regimes warmer or cooler than the "optimum'' result in small and less fecund adults Two hypotheses concerning river water temperatures and size variation of adult insects are described First, maximum adult size reflects an equilibrium between several developmental processes that appear highly temperature dependent, viz, (i) the rate and duration of larval growth, and (ii) the specific time in larval development that adult structures begin maturing and the rate of this maturation process Second, a species distribution both locally within drainage systems and over a large geographic area is limited, in part, by lowered fecundity as adult size gradually diminishes in streams of increasingly cold or warm temperature cycles The importance of riv
787 citations